I am using a MSP430F1121A and I cannot understand the times of instructions. I seem to have it ok but when checking on a scope I find it is not correct. I am using a 32KHz crystal and using this for MCLK. I have the following instruction bis.b #ENABLE,&P1OUT, bic.b #ENABLE,&P1OUT bis.b #ENABLE,&P1OUT. I would have thought this instruction would take 5 cycles from what I read in the user guide but the positive pulse width I read is 122 microseconds which indicates a 4 cycle instruction. (1/327680.52 microseconds). Can someone point me in the right direction?? Thanks Peter
Instruction cycles
Started by ●July 16, 2003
Reply by ●July 16, 20032003-07-16
Peter,
> I am using a MSP430F1121A and I cannot understand
the times of
> instructions. I seem to have it ok but when checking on a
> scope I find it
> is not correct.
> I am using a 32KHz crystal and using this for MCLK. I have
> the following
> instruction
> bis.b #ENABLE,&P1OUT,
> bic.b #ENABLE,&P1OUT
> bis.b #ENABLE,&P1OUT.
> I would have thought this instruction would take 5 cycles
> from what I read
> in the user guide but the positive pulse width I read is 122
> microseconds
> which indicates a 4 cycle instruction. (1/327680.52
> microseconds). Can
> someone point me in the right direction??
Ok, if ENABLE is not 0x01, 0x02, 0x04, or 0x08, 0x00, or 0xff, then
bic.b #ENABLE, &P1OUT is encoded as this:
bic.b @pc+, P1OUT(R3) ; R3 fixed to zero
This would take five cycles to execute. However, if ENABLE is one of
the special values mentioned above, then the constant generator is used
for the source, knocking off one cycle. The actual encoding of the
instruction is dependent upon the constant, but it takes fewer words to
encode (one less, in fact).
If you need five cycles, add a NOP after then original instruction. NOP
is encoded as MOV R3, R3 and takes a single cycle to execute.
-- Paul.
Reply by ●July 16, 20032003-07-16
At 09:48 AM 16/07/2003 +0100, you wrote:
Thanks Paul,
but where on earth did you find this information, specifically??
Peter
>Peter,
>
> > I am using a MSP430F1121A and I cannot understand the times of
> > instructions. I seem to have it ok but when checking on a
> > scope I find it
> > is not correct.
> > I am using a 32KHz crystal and using this for MCLK. I have
> > the following
> > instruction
> > bis.b #ENABLE,&P1OUT,
> > bic.b #ENABLE,&P1OUT
> > bis.b #ENABLE,&P1OUT.
> > I would have thought this instruction would take 5 cycles
> > from what I read
> > in the user guide but the positive pulse width I read is 122
> > microseconds
> > which indicates a 4 cycle instruction. (1/327680.52
> > microseconds). Can
> > someone point me in the right direction??
>
>Ok, if ENABLE is not 0x01, 0x02, 0x04, or 0x08, 0x00, or 0xff, then
>bic.b #ENABLE, &P1OUT is encoded as this:
>
> bic.b @pc+, P1OUT(R3) ; R3 fixed to zero
>
>This would take five cycles to execute. However, if ENABLE is one of
>the special values mentioned above, then the constant generator is used
>for the source, knocking off one cycle. The actual encoding of the
>instruction is dependent upon the constant, but it takes fewer words to
>encode (one less, in fact).
>
>If you need five cycles, add a NOP after then original instruction. NOP
>is encoded as MOV R3, R3 and takes a single cycle to execute.
>
>-- Paul.
>
>
>.
>
>
>
>">http://docs.yahoo.com/info/terms/
Reply by ●July 16, 20032003-07-16
What is the value of #ENABLE? remember that masks can also use the
Constant Generator registers, so choose wisely Grasshopper, and
interpret the path with care.
BIS.B Rx,&P1OUT is a 4 cycle instruction.
Al
Peter Grey wrote:
> I am using a MSP430F1121A and I cannot understand
the times of
> instructions. I seem to have it ok but when checking on a scope I find it
> is not correct.
> I am using a 32KHz crystal and using this for MCLK. I have the following
> instruction
> bis.b #ENABLE,&P1OUT,
> bic.b #ENABLE,&P1OUT
> bis.b #ENABLE,&P1OUT.
> I would have thought this instruction would take 5 cycles from what I read
> in the user guide but the positive pulse width I read is 122 microseconds
> which indicates a 4 cycle instruction. (1/327680.52 microseconds). Can
> someone point me in the right direction??
>
> Thanks
>
>
> Peter
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●July 16, 20032003-07-16
Peter,
> Thanks Paul,
> but where on earth did you find this information, specifically??
Cycle information is in each of the family manuals, e.g. Table 5-2 for
format I instruction in SLAA049B p. 5-15. Constant generator is
described in 5.1.4 in the same manual.
-- Paul.
Reply by ●July 16, 20032003-07-16
Chapter 7 of SLAA024. It is there in SLAUO49, but it is not immediately
obvious.
AL
Peter Grey wrote:
> At 09:48 AM 16/07/2003 +0100, you wrote:
>
> Thanks Paul,
> but where on earth did you find this information, specifically??
>
> Peter
>
>>Peter,
>>
>>
>>>I am using a MSP430F1121A and I cannot understand the times of
>>>instructions. I seem to have it ok but when checking on a
>>>scope I find it
>>>is not correct.
>>>I am using a 32KHz crystal and using this for MCLK. I have
>>>the following
>>>instruction
>>>bis.b #ENABLE,&P1OUT,
>>>bic.b #ENABLE,&P1OUT
>>>bis.b #ENABLE,&P1OUT.
>>>I would have thought this instruction would take 5 cycles
>>>from what I read
>>>in the user guide but the positive pulse width I read is 122
>>>microseconds
>>>which indicates a 4 cycle instruction. (1/327680.52
>>>microseconds). Can
>>>someone point me in the right direction??
>>
>>Ok, if ENABLE is not 0x01, 0x02, 0x04, or 0x08, 0x00, or 0xff, then
>>bic.b #ENABLE, &P1OUT is encoded as this:
>>
>> bic.b @pc+, P1OUT(R3) ; R3 fixed to zero
>>
>>This would take five cycles to execute. However, if ENABLE is one of
>>the special values mentioned above, then the constant generator is used
>>for the source, knocking off one cycle. The actual encoding of the
>>instruction is dependent upon the constant, but it takes fewer words to
>>encode (one less, in fact).
>>
>>If you need five cycles, add a NOP after then original instruction. NOP
>>is encoded as MOV R3, R3 and takes a single cycle to execute.
>>
>>-- Paul.
>>
>>
>>.
>>
>>
>>
>>">http://docs.yahoo.com/info/terms/
>
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●July 16, 20032003-07-16
Hi all, I have read '5.2.8 clock cycles, length of instructions'... and this didn't seem to make much sense to me. Is there anyone out there who can shed some light on this subject in PLAIN english. Motorola has good documentation on cycles/Instructions etc which is very easy to understand. TI's documentation seems to be hidden inside of IF, Else statements,.....my opinion anyway. I will run out of hair it I scratch my head any longer. Dennis
Reply by ●July 17, 20032003-07-17
Hi dennis. The first thing to do is to determine if the instruction is
emulated or not, and what the emulation is. Next you have to determine
the instruction format. Finally you need to decode the register usage
that applies, if any. Format 1 are most instrcutions. Format 2 are
instructions that have a destination but no source. ie INST dst
RRA/RRC/SWPB/SXT ARE FORMAT2, i'LL CALL TYPEX. PUSH/CALL ARE FORMAT 2
I'LL CALL TYPEY
All jumps 2c ;FORMAT 3 INSTRUCTIONS
RETI 5C ;MISC
TYPEX Rx 1C
TYPEX n(Rx) 4C
TYPEX FOO 4C
TYPEX &FOO 4C
TYPEX @Rx 3C
TYPEX @Rx+ 3C BUT SHOULDN'T BE USED
TYPEX #100 3C
PUSH Rx 3C
CALL Rx 4C
TYPEY n(Rx) 5C
TYPEY FOO 5C
TYPEY &FOO 5C
TYPEY @Rx 4C
PUSH @Rx+ 4C
PUSH #100 4C
CALL @Rx+ 5C
CALL #100 5C
FORMAT 1 INSTRUCTIONS are those with src and dst, eg MOV src,dst, to
illustrate using MOV
SINGLE CYCLE:
MOV R14,R15
TWO CYCLE INSTRUCTIONS
MOV R14,PC
MOV @R14,R15
MOV @R14+,R15
MOV #100,R15
THREE CYCLE INSTRUCTIONS
MOV x(R14),R15
MOV FOO,R15
MOV &FOO,R15
MOV @R14+,PC
MOV #100,PC
FOUR CYCLE INSTRUCTIONS
MOV R14,x(R15)
MOV R14,FOO
MOV R14,&FOO
FIVE CYCLE INSTRUCTIONS
MOV @R14,x(R15)
MOV @R14,FOO
MOV @R14,&FOO
MOV @R14+,x(R15)
MOV @R14+,FOO
MOV @R14+,&FOO
MOV #100,x(R15)
MOV #100,FOO
MOV #100,&FOO
SIX CYCLE INSTRUCTIONS
MOV x(R14),x(R15)
MOV x(R14),FOO
MOV x(R14,&F00
MOV FOO,x(R15)
MOV FOO2,FOO
MOV FOO2,&F00
MOV &FOO,x(R15)
MOV &FOO2,FOO
MOV &FOO2,&F00
In the above lists R14 and R15 represent any register except the
constant generators and, where indicated, PC. #100 represents any
absolute value in range. FOO is a label/name. Where either src or dst
can be resolved to a value supplied by a constant register then the
register format will be automatically substituted. For example:-
MOV #0,R14 APPEARS TO BE A 2 CYCLE INSTRUCTION, BUT WILL ENCODE AS A
SINGLE CYCLE INSTRUCTION SINCE 0 IS SUPPLIED BY THE CONSTANT GENERATOR.
AL
Dennis McGrath wrote:
> Hi all,
>
> I have read '5.2.8 clock cycles, length of instructions'... and
this didn't seem to make
> much sense to me. Is there anyone out there who can shed some light on this
subject in
> PLAIN english.
> Motorola has good documentation on cycles/Instructions etc which is very
easy to understand.
> TI's documentation seems to be hidden inside of IF, Else
statements,.....my opinion anyway.
> I will run out of hair it I scratch my head any longer.
>
> Dennis
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●July 17, 20032003-07-17
On 17 Jul 2003 at 16:52, onestone wrote:
> Hi dennis. The first thing to do is to determine
if the instruction is
> emulated or not, and what the emulation is. Next you have to determine
> the instruction format. Finally you need to decode the register usage
> that applies, if any. Format 1 are most instrcutions. Format 2 are
> instructions that have a destination but no source. ie INST dst
>
> RRA/RRC/SWPB/SXT ARE FORMAT2, i'LL CALL TYPEX. PUSH/CALL ARE FORMAT 2
> I'LL CALL TYPEY
>
>
> All jumps 2c ;FORMAT 3 INSTRUCTIONS
> RETI 5C ;MISC
> TYPEX Rx 1C
> TYPEX n(Rx) 4C
> TYPEX FOO 4C
> TYPEX &FOO 4C
> TYPEX @Rx 3C
> TYPEX @Rx+ 3C BUT SHOULDN'T BE USED
> TYPEX #100 3C
> PUSH Rx 3C
> CALL Rx 4C
> TYPEY n(Rx) 5C
> TYPEY FOO 5C
> TYPEY &FOO 5C
> TYPEY @Rx 4C
> PUSH @Rx+ 4C
> PUSH #100 4C
> CALL @Rx+ 5C
> CALL #100 5C
>
> FORMAT 1 INSTRUCTIONS are those with src and dst, eg MOV src,dst, to
> illustrate using MOV
>
> SINGLE CYCLE:
>
> MOV R14,R15
>
> TWO CYCLE INSTRUCTIONS
>
> MOV R14,PC
> MOV @R14,R15
> MOV @R14+,R15
> MOV #100,R15
>
> THREE CYCLE INSTRUCTIONS
>
> MOV x(R14),R15
> MOV FOO,R15
> MOV &FOO,R15
> MOV @R14+,PC
> MOV #100,PC
>
> FOUR CYCLE INSTRUCTIONS
>
> MOV R14,x(R15)
> MOV R14,FOO
> MOV R14,&FOO
>
> FIVE CYCLE INSTRUCTIONS
>
> MOV @R14,x(R15)
> MOV @R14,FOO
> MOV @R14,&FOO
> MOV @R14+,x(R15)
> MOV @R14+,FOO
> MOV @R14+,&FOO
> MOV #100,x(R15)
> MOV #100,FOO
> MOV #100,&FOO
>
> SIX CYCLE INSTRUCTIONS
>
> MOV x(R14),x(R15)
> MOV x(R14),FOO
> MOV x(R14,&F00
> MOV FOO,x(R15)
> MOV FOO2,FOO
> MOV FOO2,&F00
> MOV &FOO,x(R15)
> MOV &FOO2,FOO
> MOV &FOO2,&F00
>
> In the above lists R14 and R15 represent any register except the
> constant generators and, where indicated, PC. #100 represents any
> absolute value in range. FOO is a label/name. Where either src or dst
> can be resolved to a value supplied by a constant register then the
> register format will be automatically substituted. For example:-
>
> MOV #0,R14 APPEARS TO BE A 2 CYCLE INSTRUCTION, BUT WILL ENCODE AS A
> SINGLE CYCLE INSTRUCTION SINCE 0 IS SUPPLIED BY THE CONSTANT GENERATOR.
>
> AL
Thanks Al,
This is just what I needed, though I do feel I can no longer mention the
wallabies game
with South Africa last week since you have gone to so much trouble to answer my
question.
Simply Thanx
Dennis
Reply by ●July 17, 20032003-07-17
Dennis McGrath wrote:
> On 17 Jul 2003 at 16:52, onestone wrote:
>
>
>>Hi dennis. The first thing to do is to determine if the instruction is
>>emulated or not, and what the emulation is. Next you have to determine
>>the instruction format. Finally you need to decode the register usage
>>that applies, if any. Format 1 are most instrcutions. Format 2 are
>>instructions that have a destination but no source. ie INST dst
>>
>>RRA/RRC/SWPB/SXT ARE FORMAT2, i'LL CALL TYPEX. PUSH/CALL ARE FORMAT
2
>>I'LL CALL TYPEY
>>
>>
>>All jumps 2c ;FORMAT 3 INSTRUCTIONS
>>RETI 5C ;MISC
>>TYPEX Rx 1C
>>TYPEX n(Rx) 4C
>>TYPEX FOO 4C
>>TYPEX &FOO 4C
>>TYPEX @Rx 3C
>>TYPEX @Rx+ 3C BUT SHOULDN'T BE USED
>>TYPEX #100 3C
>>PUSH Rx 3C
>>CALL Rx 4C
>>TYPEY n(Rx) 5C
>>TYPEY FOO 5C
>>TYPEY &FOO 5C
>>TYPEY @Rx 4C
>>PUSH @Rx+ 4C
>>PUSH #100 4C
>>CALL @Rx+ 5C
>>CALL #100 5C
>>
>>FORMAT 1 INSTRUCTIONS are those with src and dst, eg MOV src,dst, to
>>illustrate using MOV
>>
>>SINGLE CYCLE:
>>
>>MOV R14,R15
>>
>>TWO CYCLE INSTRUCTIONS
>>
>>MOV R14,PC
>>MOV @R14,R15
>>MOV @R14+,R15
>>MOV #100,R15
>>
>>THREE CYCLE INSTRUCTIONS
>>
>>MOV x(R14),R15
>>MOV FOO,R15
>>MOV &FOO,R15
>>MOV @R14+,PC
>>MOV #100,PC
>>
>>FOUR CYCLE INSTRUCTIONS
>>
>>MOV R14,x(R15)
>>MOV R14,FOO
>>MOV R14,&FOO
>>
>>FIVE CYCLE INSTRUCTIONS
>>
>>MOV @R14,x(R15)
>>MOV @R14,FOO
>>MOV @R14,&FOO
>>MOV @R14+,x(R15)
>>MOV @R14+,FOO
>>MOV @R14+,&FOO
>>MOV #100,x(R15)
>>MOV #100,FOO
>>MOV #100,&FOO
>>
>>SIX CYCLE INSTRUCTIONS
>>
>>MOV x(R14),x(R15)
>>MOV x(R14),FOO
>>MOV x(R14,&F00
>>MOV FOO,x(R15)
>>MOV FOO2,FOO
>>MOV FOO2,&F00
>>MOV &FOO,x(R15)
>>MOV &FOO2,FOO
>>MOV &FOO2,&F00
>>
>>In the above lists R14 and R15 represent any register except the
>>constant generators and, where indicated, PC. #100 represents any
>>absolute value in range. FOO is a label/name. Where either src or dst
>>can be resolved to a value supplied by a constant register then the
>>register format will be automatically substituted. For example:-
>>
>>MOV #0,R14 APPEARS TO BE A 2 CYCLE INSTRUCTION, BUT WILL ENCODE AS A
>>SINGLE CYCLE INSTRUCTION SINCE 0 IS SUPPLIED BY THE CONSTANT GENERATOR.
>>
>>AL
>
> Thanks Al,
> This is just what I needed, though I do feel I can no longer mention the
wallabies game
> with South Africa last week since you have gone to so much trouble to
answer my
> question.
> Simply Thanx
> Dennis
That was simply a cunning tactic, having dominated world rugby for so
long the rest of you were becoming dispirited, pareticularly the South
Africans, we needed to re-stimulate world interest in the game, to keep
tyhe crowds up, by thinking their team might actually stand a chance
against us.
You're welcome by the way.
Al
